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| 1200 | jermar | 1 | /* |
| 2 | * Copyright (C) 2006 Jakub Jermar |
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| 3 | * All rights reserved. |
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| 4 | * |
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| 5 | * Redistribution and use in source and binary forms, with or without |
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| 6 | * modification, are permitted provided that the following conditions |
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| 7 | * are met: |
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| 8 | * |
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| 9 | * - Redistributions of source code must retain the above copyright |
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| 10 | * notice, this list of conditions and the following disclaimer. |
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| 11 | * - Redistributions in binary form must reproduce the above copyright |
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| 12 | * notice, this list of conditions and the following disclaimer in the |
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| 13 | * documentation and/or other materials provided with the distribution. |
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| 14 | * - The name of the author may not be used to endorse or promote products |
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| 15 | * derived from this software without specific prior written permission. |
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| 16 | * |
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| 17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
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| 18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
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| 19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
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| 20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
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| 21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
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| 22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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| 23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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| 24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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| 25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
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| 26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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| 27 | */ |
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| 28 | |||
| 1702 | cejka | 29 | /** @addtogroup genericadt ADT |
| 30 | * @ingroup kernel |
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| 31 | * @{ |
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| 32 | */ |
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| 1248 | jermar | 33 | /** |
| 34 | * @file bitmap.c |
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| 35 | * @brief Implementation of bitmap ADT. |
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| 36 | * |
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| 37 | * This file implements bitmap ADT and provides functions for |
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| 38 | * setting and clearing ranges of bits. |
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| 39 | */ |
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| 40 | |||
| 1200 | jermar | 41 | #include <adt/bitmap.h> |
| 42 | #include <typedefs.h> |
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| 43 | #include <arch/types.h> |
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| 44 | #include <align.h> |
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| 45 | #include <debug.h> |
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| 1262 | jermar | 46 | #include <macros.h> |
| 1200 | jermar | 47 | |
| 48 | #define ALL_ONES 0xff |
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| 49 | #define ALL_ZEROES 0x00 |
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| 50 | |||
| 51 | /** Initialize bitmap. |
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| 52 | * |
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| 53 | * No portion of the bitmap is set or cleared by this function. |
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| 54 | * |
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| 55 | * @param bitmap Bitmap structure. |
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| 56 | * @param map Address of the memory used to hold the map. |
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| 57 | * @param bits Number of bits stored in bitmap. |
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| 58 | */ |
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| 59 | void bitmap_initialize(bitmap_t *bitmap, __u8 *map, count_t bits) |
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| 60 | { |
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| 61 | bitmap->map = map; |
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| 62 | bitmap->bits = bits; |
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| 63 | } |
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| 64 | |||
| 65 | /** Set range of bits. |
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| 66 | * |
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| 67 | * @param bitmap Bitmap structure. |
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| 68 | * @param start Starting bit. |
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| 69 | * @param bits Number of bits to set. |
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| 70 | */ |
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| 71 | void bitmap_set_range(bitmap_t *bitmap, index_t start, count_t bits) |
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| 72 | { |
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| 1549 | vana | 73 | index_t i=0; |
| 1200 | jermar | 74 | index_t aligned_start; |
| 75 | count_t lub; /* leading unaligned bits */ |
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| 1262 | jermar | 76 | count_t amb; /* aligned middle bits */ |
| 77 | count_t tab; /* trailing aligned bits */ |
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| 1200 | jermar | 78 | |
| 79 | ASSERT(start + bits <= bitmap->bits); |
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| 80 | |||
| 81 | aligned_start = ALIGN_UP(start, 8); |
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| 1262 | jermar | 82 | lub = min(aligned_start - start, bits); |
| 83 | amb = bits > lub ? bits - lub : 0; |
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| 84 | tab = amb % 8; |
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| 1200 | jermar | 85 | |
| 1549 | vana | 86 | if ( start + bits < aligned_start ) { |
| 87 | /* |
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| 88 | * Set bits in the middle of byte |
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| 89 | */ |
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| 90 | bitmap->map[start / 8] |= ((1 << lub)-1) << (start&7); |
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| 91 | return; |
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| 92 | } |
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| 93 | |||
| 1200 | jermar | 94 | if (lub) { |
| 95 | /* |
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| 96 | * Make sure to set any leading unaligned bits. |
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| 97 | */ |
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| 98 | bitmap->map[start / 8] |= ~((1 << (8 - lub)) - 1); |
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| 99 | } |
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| 1262 | jermar | 100 | for (i = 0; i < amb / 8; i++) { |
| 1200 | jermar | 101 | /* |
| 102 | * The middle bits can be set byte by byte. |
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| 103 | */ |
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| 104 | bitmap->map[aligned_start / 8 + i] = ALL_ONES; |
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| 105 | } |
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| 1262 | jermar | 106 | if (tab) { |
| 1200 | jermar | 107 | /* |
| 1262 | jermar | 108 | * Make sure to set any trailing aligned bits. |
| 1200 | jermar | 109 | */ |
| 1262 | jermar | 110 | bitmap->map[aligned_start / 8 + i] |= (1 << tab) - 1; |
| 1200 | jermar | 111 | } |
| 112 | |||
| 113 | } |
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| 114 | |||
| 115 | /** Clear range of bits. |
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| 116 | * |
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| 117 | * @param bitmap Bitmap structure. |
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| 118 | * @param start Starting bit. |
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| 119 | * @param bits Number of bits to clear. |
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| 120 | */ |
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| 121 | void bitmap_clear_range(bitmap_t *bitmap, index_t start, count_t bits) |
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| 122 | { |
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| 1549 | vana | 123 | index_t i=0; |
| 1200 | jermar | 124 | index_t aligned_start; |
| 125 | count_t lub; /* leading unaligned bits */ |
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| 1262 | jermar | 126 | count_t amb; /* aligned middle bits */ |
| 127 | count_t tab; /* trailing aligned bits */ |
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| 1200 | jermar | 128 | |
| 129 | ASSERT(start + bits <= bitmap->bits); |
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| 130 | |||
| 131 | aligned_start = ALIGN_UP(start, 8); |
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| 1262 | jermar | 132 | lub = min(aligned_start - start, bits); |
| 133 | amb = bits > lub ? bits - lub : 0; |
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| 134 | tab = amb % 8; |
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| 135 | |||
| 1549 | vana | 136 | if ( start + bits < aligned_start ) |
| 137 | { |
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| 138 | /* |
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| 139 | * Set bits in the middle of byte |
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| 140 | */ |
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| 141 | bitmap->map[start / 8] &= ~(((1 << lub)-1) << (start&7)); |
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| 142 | return; |
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| 143 | } |
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| 144 | |||
| 145 | |||
| 1200 | jermar | 146 | if (lub) { |
| 147 | /* |
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| 148 | * Make sure to clear any leading unaligned bits. |
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| 149 | */ |
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| 150 | bitmap->map[start / 8] &= (1 << (8 - lub)) - 1; |
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| 151 | } |
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| 1262 | jermar | 152 | for (i = 0; i < amb / 8; i++) { |
| 1200 | jermar | 153 | /* |
| 154 | * The middle bits can be cleared byte by byte. |
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| 155 | */ |
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| 156 | bitmap->map[aligned_start / 8 + i] = ALL_ZEROES; |
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| 157 | } |
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| 1262 | jermar | 158 | if (tab) { |
| 1200 | jermar | 159 | /* |
| 1262 | jermar | 160 | * Make sure to clear any trailing aligned bits. |
| 1200 | jermar | 161 | */ |
| 1262 | jermar | 162 | bitmap->map[aligned_start / 8 + i] &= ~((1 << tab) - 1); |
| 1200 | jermar | 163 | } |
| 1262 | jermar | 164 | |
| 1200 | jermar | 165 | } |
| 166 | |||
| 167 | /** Copy portion of one bitmap into another bitmap. |
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| 168 | * |
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| 169 | * @param dst Destination bitmap. |
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| 170 | * @param src Source bitmap. |
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| 171 | * @param bits Number of bits to copy. |
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| 172 | */ |
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| 173 | void bitmap_copy(bitmap_t *dst, bitmap_t *src, count_t bits) |
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| 174 | { |
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| 175 | index_t i; |
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| 176 | |||
| 177 | ASSERT(bits <= dst->bits); |
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| 178 | ASSERT(bits <= src->bits); |
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| 179 | |||
| 180 | for (i = 0; i < bits / 8; i++) |
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| 181 | dst->map[i] = src->map[i]; |
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| 182 | |||
| 183 | if (bits % 8) { |
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| 184 | bitmap_clear_range(dst, i * 8, bits % 8); |
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| 185 | dst->map[i] |= src->map[i] & ((1 << (bits % 8)) - 1); |
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| 186 | } |
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| 187 | } |
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| 1702 | cejka | 188 | |
| 189 | /** @} |
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| 190 | */ |
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| 191 |